1. Field of the Invention
The present invention provides a method for disconnecting a transceiver from a bus in multipoint/multidrop architecture by using a controller in which a signal comparator and a failure detection controller are installed for detection and judgment if the transceiver or the bus fails, and by using a relay that enables connection or disconnection between the bus and the transceiver to ensure that the bus and the transceiver work continuously without generating effect on each others.
2. Description of the Related Art
With popularity of Internet and continuous evolution in science and technology, the traditionally labor-intensive enterprises have gradually turned to manufacturing techniques that rely on communication and data transfer between the various equipments instead of a lot of manpower. Installation of highly automatic equipments can not only allow enterprises to reduce their labor costs that are very high, but also contribute to reducing the risks caused by talent flows. With these automatic equipments in place, overall production processes can be implemented mostly by these equipments, where the multipoint/multidrop network architecture technology currently serves as the mechanism of exchange and communication among different equipments.
Generally speaking, in the multipoint architecture, enterprises link all complex communication devices on the bus with the system via a communication interface to ensure interoperability of the complex communication equipments and the system. Under such condition, however, a short circuit or abnormality of any device in the system or bus will lead to communication failure of all complex communication equipments.
Referring to FIG. 5, in the multipoint architecture, there is a system A that includes a central processing unit (CPU) A1 and a universal asynchronous receiver transmitter (UART) A2. The CPU A1 and the UART A2 are linked to a bus C via a transceiver B. In addition, the bus C comprises a plurality of communication equipments C1.
Referring to FIG. 6, when a short circuit occurs in a first device C11 of the communication equipments C1, a plurality of second devices C12 on the bus C will not operate. Moreover in such architecture, it is impossible to learn whether the transceiver B or the first device C11 on the bus C fails. Therefore, a maintenance person must waste more time in deciding whether the failure occurs in the transceiver B or in the first device C11.
Referring to FIG. 7, when the transceiver B is damaged, it will cause the communication equipments C1 on the bus C to be abnormal, thus making the communication equipments C1 unable to intercommunicate successfully. Besides, when the maintenance person arrives, they need to spend much time in re-inspecting to the communication equipments C1, because they are not uncertain whether the failure occurs in the transceiver B or in the communication equipments C1 of the bus C.
Hence, for the firms that utilize machines and equipments as an essential means of production, any failure of the transceiver will immediately lead to disability of the bus, and it also takes them considerable time to examine the devices where the failure occurs. Under such circumstances, the downtime resulting from interaction of these equipments will last for a longer period, which will not only cause losses in tangible costs and profits of these enterprises, but also have impact on their intangible reputation, as they may be unable to deliver goods on schedule to their customers. As a result, these enterprises may find it difficult to continue their cooperation with customers in the future, which in turn will cause great damage to the enterprises themselves.